Re^4: eval sub

Thanks again almut. I understand and agree with what you are saying. I checked for the errors and this is what I got "error: Can't find string terminator '"' anywhere before EOF at (eval 5) line 1."

This made me realize that even though I might be quoting the arguments string in the code posted here correctly, I wasn't doing that right in the actual code where I also needed to first escape both $ in my hash to be \$\$myHash. Adding that extra stuff fixed it. I didn't even think that was the problem - there's a duh! moment. :)

While I am not sure why I wasn't getting the "Too many arguments..." error in my direct call to mySub("Hello world"), it is likely I would have got that error once I actually quoted my string right in the eval. I added the direct call in your code to highlight what I am saying about not getting the error when making the direct call:

my $code = << 'EOC';
sub mySub() {
    print "args: @_\n";
}
EOC

eval $code;

print qq(\ncalling 'mySub()'\n);
eval 'mySub()';
print "error: $@" if $@;

print qq(\ncalling 'mySub("hello world")' directly\n);
mySub("hello world");

print qq(\ncalling 'mySub("hello world")'\n);
eval 'mySub("hello world")';
print "error: $@" if $@;
[download]

Running this returned:

calling 'mySub()'
args:

calling 'mySub("hello world")' directly
args: hello world

calling 'mySub("hello world")'
error: Too many arguments for main::mySub at (eval 3) line 2, near ""h
+ello world")"
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Re^5: eval sub by almut (Canon) on Oct 10, 2008 at 14:41 UTC
...I am not sure why I wasn't getting the "Too many arguments..." error in my direct call to mySub("Hello world") The reason for this is that the error is thrown at compile time. In the case of the direct call, the subroutine definition (and its prototype) isn't known yet, as it gets `eval`-ed later at runtime... Put that code in a `BEGIN {...}` block, i.e. `BEGIN { my $code = << 'EOC'; sub mySub() { print "args: @_\n"; } EOC eval $code; } ...` [download] and you'll see the difference. Due to the compilation error, the script now doesn't run at all: `$ ./716452.pl Too many arguments for main::mySub at ./716452.pl line 19, near ""hell +o world")" Execution of ./716452.pl aborted due to compilation errors.` [download]	[reply] [d/l] [select]

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Re^5: eval sub
by almut (Canon) on Oct 10, 2008 at 14:41 UTC

...I am not sure why I wasn't getting the "Too many arguments..." error in my direct call to mySub("Hello world")

The reason for this is that the error is thrown at compile time. In the case of the direct call, the subroutine definition (and its prototype) isn't known yet, as it gets eval-ed later at runtime...

Put that code in a BEGIN {...} block, i.e.

BEGIN {
    my $code = << 'EOC';
    sub mySub() {
        print "args: @_\n";
    }
EOC
    
    eval $code;
}
...
[download]

and you'll see the difference. Due to the compilation error, the script now doesn't run at all:

$ ./716452.pl
Too many arguments for main::mySub at ./716452.pl line 19, near ""hell
+o world")"
Execution of ./716452.pl aborted due to compilation errors.
[download]

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